A new report has revealed that the rice supply in at least 30 countries may have already been contaminated with genetically modified strains from US exports, thereby threatening worldwide contamination.

A new report by the GM Contamination Register has disclosed US Department of Agriculture findings from 2006 and 2007, which show that the department detected traces of unapproved GM rice in over 30 countries. At the time, all of the Bayer CropScience varieties discovered had not been approved for cultivation or consumption abroad, and only one of the three types had been approved for domestic cultivation.

The USDA believes that the source of the contamination is field trials which occurred between the mid 1990s and early 2000s.The genetically modified LLRICE62, LLRice601 and LLRICE604 varieties are herbicide resistant. The trials were terminated in 2002 and none of these varieties ever made it onto the US market. But years later, traces of these strands were found worldwide.

The USDA report said the agency was unable to conclude whether pollen from the trials escaped and contaminated other fields or mechanical mixing was to blame.

News of the USDA’s findings comes after Monsanto’s unapproved GM wheat made its way onto an Oregon field, threatening US supplies and making other countries weary of importing US crops. GM wheat has not been approved for cultivation anywhere in the world. The US is the world’s largest exporter of wheat, and many of its trading partners are fiercely opposed to the use of GM wheat supplies. After news of the contaminated Oregon farm broke out, Japan and South Korea suspended some of its imports of American wheat, and the European Union urged its member nations to test for any contamination in its imports.

When experimental crop strains escape into general seed supplies, it is difficult to keep them contained, prompting some countries to pull US rice off their shelves.

“Scientific studies confirm that GM contamination is unavoidable once GM crops are grown in a region,” Earth Open Source wrote in a report. “‘Coexistence’ rapidly results in widespread contamination of non-GM crops… through cross-pollination, spread of GM seed by farm machinery, and inadvertent mixing during storage.”

The USDA report notes that the rice contamination “has had a major impact on US rice exports,” prompting Russia and Bulgaria to ban US rice imports and causing numerous other countries to conduct strict certification and testing of all rice imports.

The report also notes that the contamination has affected US farmers financially, costing them billions of dollars to try to eradicate the unapproved varieties.

“The contamination episode has also affected seed producers,” the report states. “[A]n entire non-GM rice variety Clearfield 131 was banned by U.S. regulators in early 2007 when it was found to be contaminated, costing producer BASF billions of dollars in losses.”

Bayer has attempted to acquire approval for its contaminating rice strands. The USDA approved commercial growing of LL601 in 2006 and approved Canadian import of LL62 in 2006, but none of the GM rice strands are available on the US market.